ASVAB Mechanical Comprehension Practice Test 569745 Results

	Your Results	Global Average
Questions	5	5
Correct	0	3.10
Score	0%	62%

Review

1 If the handles of a wheelbarrow are 2.5 ft. from the wheel axle, how many pounds of force must you exert to lift the handles if it's carrying a 220 lbs. load concentrated at a point 1.0 ft. from the axle?

52% Answer Correctly

	52.1
	-69
	88
	None of these is correct

Solution

This problem describes a second-class lever and, for a second class lever, the effort force multiplied by the effort distance equals the resistance force multipied by the resistance distance: F_ed_e = F_rd_r. In this problem we're looking for effort force:
\( F_e = \frac{F_r d_r}{d_e} \)
\( F_e = \frac{220 \times 1.0}{2.5} \)
\( F_e = \frac{220.0}{2.5} \)
\( F_e = 88 \)

Coplanar forces:

62% Answer Correctly

	pass through a common point
	have opposite dimensions
	act along the same line of action
	act in a common plane

Solution

Collinear forces act along the same line of action, concurrent forces pass through a common point and coplanar forces act in a common plane.

A ramp is an example of which kind of simple machine?

85% Answer Correctly

	wedge
	none of these
	first-class lever
	inclined plane

Solution

An inclined plane is a simple machine that reduces the force needed to raise an object to a certain height. Work equals force x distance and, by increasing the distance that the object travels, an inclined plane reduces the force necessary to raise it to a particular height. In this case, the mechanical advantage is to make the task easier. An example of an inclined plane is a ramp.

A truck is using a rope to pull a car. Tension in the rope is greatest in which of the following places?

50% Answer Correctly

	near the truck
	in the middle
	near the car
	tension is equal in all parts of the rope

Solution

Tension is a force that stretches or elongates something. When a cable or rope is used to pull an object, for example, it stretches internally as it accepts the weight that it's moving. Although tension is often treated as applying equally to all parts of a material, it's greater at the places where the material is under the most stress.

What type of load creates different stresses at different locations on a structure?

61% Answer Correctly

	static uniformly distributed load
	dynamic load
	impact load
	non-uniformly distributed load

Solution

A concentrated load acts on a relatively small area of a structure, a static uniformly distributed load doesn't create specific stress points or vary with time, a dynamic load varies with time or affects a structure that experiences a high degree of movement, an impact load is sudden and for a relatively short duration and a non-uniformly distributed load creates different stresses at different locations on a structure.